A QHI at Shawbury once took control from his student in a Gazelle in a confined area to debrief him - for some reason he took the cyclic in his left hand and the RHS pilots collective in his right. They promptly speared in (survived with few injuries) not surprisingly. As a result of this crash we had to put student QHIs in the LHS of the Gazelle and let them try to hover it in this fashion - just to prove what a stupid idea it was. With practise it can be achieved but more often an brief period of relative stability is followed by a rapidly worsening situation as the pilot tries to use his left hand (now on the cyclic) to correct the height errors and his right hand to selct the hover attitude.